7A Chemistry Review

1. All matter is made up of ATOMS.

A A – Electron B B – Neutron C - Proton C 2. Identify each labeled structure in the atom. Describe the charge for each particle. A A – Electron Electrons have a negative charge. B B – Neutron Neutrons have no charge (neutral). C - Proton Protons have a positive charge. C

3.Where are protons and neutrons found in an atom? 4. Where are electrons found in an atom? In the nucleus of an atom. Outside the nucleus of an atom.

5. Which subatomic particle would be found outside the nucleus of an atom? ELECTRON

6. A positively charged particle is a PROTON.

3 7. Which of the following is not an element? 1. oxygen 3. sodium chloride 2. hydrogen 4. nitrogen 3

4 8. A chemical formula like CO2 represents an element 3. an atom an electron  4. a compound 4

9. A substance made up of two or more elements that have been chemically combined is a COMPOUND.

10. A substance made up of two or more elements that have been physcially combined is a MIXTURE.

11. A substance that cannot be changed into simpler substances by a chemical change is called a (an) 1. element. 3. liquid. 2. solid. 4. mixture. 1

12. Element or Compound? a. Carbon (C) b. Carbon dioxide (CO2) c. Water (H2O) d. Nitrogen (N) e. Glucose (C6H12O6) element compound compound element compound

13. 3

14. Oxygen and hydrogen

15. 6

A 16. Label the following diagrams: Compound, element, mixture D B C

1 17. In sweetened tea, the sugar is called the 1. solute. 3. solvent. 2. element. 4. solution. 1

18. Which of the following would help sugar dissolve faster in water? stirring the water decreasing the solubility of sugar using larger particles of sugar decreasing the water temperature 1

19. Describe the difference between a soluble and insoluble substance. A soluble substance easily dissolves in a solvent. An insoluble substance DOES NOT dissolve in a solvent.

20. Sand and iron particles that are similar in size and color are mixed together in a beaker. What would be the best method of separating the particles? Use tweezers to separate them. Add water to the mixture. Use a magnet to separate them. Pour the mixture into a filter. 3

21. Heat up the water. Crush the sugar cube (increase its surface area). Stir the solution.

22. The substances in a mixture can be separated by physical means because no chemical change occurs when the substances are combined. the physical and chemical properties of the substances change. none of the properties of the substances change. the chemical, but not the physical, properties of the substances change. 1

23. Describe the term ‘solubility.’ The amount of solute that can dissolve in a solvent 24. Describe at least three factors that can affect the solubility of a substance. Temperature, surface area, stirring

25. Which of the following would help sugar dissolve faster in water? stirring, the water decreasing the solubility of sugar using larger particles of sugar decreasing the water temperature a

26. 36 g Heat up the water. As temperature increases, the solubility of the gas decreases. Heat up the solvent, increase the surface area, stir the solution.

27. 3

28. For the following pictures, identify whether a physical or chemical change is occurring.

Physical

Chemical

Chemical

Physical

Physical

Chemical

29. Identify substances A, C and E. Heat (thermal energy) 100 C Temperature º C. B A When the ice reaches zero degrees what starts happening? (melting from solid ice to liquid water) (click) If we were moving in the opposite direction, with decreasing energy and temperature, from liquid water to solid ice, what would that be called? (Freezing) (click) As the liquid water reaches 100 degrees, what happens? (change from liquid to gas, boiling) (click) If we were moving in the opposite direction, with decreasing energy and temperature, from water vapor to liquid water, what would that be called? (condensation, condensing) (click) Answer the questions of the bottom of your paper. Heat (thermal energy) Identify substances A, C and E. A – solid C – liquid E - gas 34

3 4 1 2 30. Heat (thermal energy) condensing evaporation freezing 100 evaporation 4 C Temperature º C. 1 B freezing melting 2 A When the ice reaches zero degrees what starts happening? (melting from solid ice to liquid water) (click) If we were moving in the opposite direction, with decreasing energy and temperature, from liquid water to solid ice, what would that be called? (Freezing) (click) As the liquid water reaches 100 degrees, what happens? (change from liquid to gas, boiling) (click) If we were moving in the opposite direction, with decreasing energy and temperature, from water vapor to liquid water, what would that be called? (condensation, condensing) (click) Answer the questions of the bottom of your paper. Heat (thermal energy) Identify processes 1, 2, 3 and 4. 1 – melting 2 – freezing 3 – vaporization 4 - condensation 35

31. The chemical composition of the can did not change. It is still made of aluminum.

32. Identify the different phases of matter. Solid, liquid, gas, plasma 33. The particles of a substance are closest together in a _____. solid 34. The particles of a substance that does not have a definite volume or shape is ____. gas

35. Identify the different phases of matter, shown in the diagram below. C liquid solid gas

36. The particles of a substance are closest together in a ____. solid 37. The particles of a substance that does not have a definite volume or shape is ______. gas 38. When a liquid becomes a solid, heat is ____ and the process is called_________. Released, freezing 39. ______ is the process in which liquid changes to gas.  evaporation

40. Matter is anything that has and _________. Mass and volume 41. Identify the following as a physical or chemical change: a. Bending a Paper Clip. physical b. Melting ice into water. c. Baking a cake batter into a cake. chemical d. The rusting of a nail

42. liquid solid

43. 3 44. 3

45. 2

- Atoms are loosely packed Solid - Atoms are tightly packed Gas 46. Identify the solid, liquid and gas! Support your answer. Liquid - Atoms are loosely packed Solid - Atoms are tightly packed Gas - Atoms are very loosely packed

a. Solid to liquid: b. Gas to liquid: c. Liquid to solid: 47. Identify the phase change described. a. Solid to liquid: b. Gas to liquid: c. Liquid to solid: d. Solid to gas: e. Liquid to gas: melting condensation freezing sublimation evaporation

48. For each phase change describe whether energy is RELEASED or ABSORBED. a. Melting: b. Freezing: c. Vaporization: d. Sublimation: e. Condensation: ABSORBED RELEASED ABSORBED ABSORBED RELEASED

1 49. The particles of a substance are closest together in a solid a liquid a gas plasma 1

3 50. The particles of a substance move most readily in a solid a liquid a gas 3

51. The particles of a substance that does not have a definite volume or shape is a solid 2. a liquid 3. a gas 3

2 52. When a liquid becomes a solid, energy does not change is released is absorbed is first absorbed, then released 2

2 53. _______ is the process in which liquid changes to gas. 1. Sublimation 3. Condensation 2. Evaporation 4. Combustion 2

1 54. The change of a liquid to a solid is called 1. freezing 3. melting 2. sublimation 4. vaporization 1

55. When substances go directly from the solid phase to the gas phase, the phase change is called 1. sublimation 2. condensation 3. evaporation 4. vaporization 1

Why didn’t the temperature of the water increase after 4 minutes? 56. In this experiment, how long did it take for the water to start boiling? 4 minutes Why didn’t the temperature of the water increase after 4 minutes? Temperature (oC) Time (minutes) The energy was being used to separate the water molecules and turn the liquid into a gas. 100 liquid How long did it take for all the water to turn into steam? 18 12 minutes 16 4

57. What happens to the position of water molecules as they lose heat energy? The slow down and move closer together.

a. Atomic mass: 79.9 b. Mass number: 80 c. # of protons: 35 d. # of electrons: e. # neutrons: 45 f. Atomic #: 58.

a. Atomic mass: 112.41 b. Mass number: 112 c. # of protons: 48 d. # of electrons: e. # neutrons: 64 f. Atomic #: 59.

2 60. All samples of an element are composed of atoms with the same atomic mass atomic number number of protons and neutrons number of neutrons 2

61. What is the atomic number for lithium? 3 3 Li Lithium 6.94 1 H Hydrogen 1.01 14 Si Silicon 28.09 18 Ar Argon 39.95 What is the atomic number for lithium? How many protons does an atom of Si have? What is the atomic mass for Argon? How many electrons does an atom of H have? How many neutrons are in an atom of Li? How many electrons are in an atom of Si? How many protons and neutrons are in an atom of Argon? 3 14 39.95 1 4 14 40

62. 4

63. 3 64. 2

65. Explain how the periodic table of elements is arranged. They are arranged according to atomic number. 66. Elements at the left of the periodic table are known as ______. metals 67. Elements at the right of the periodic table are known as _______. nonmetals

68. Explain some of the properties of metals. They are malleable, ductile, have luster, and are good conductors of heat and electricity 69. Explain some of the properties of nonmetals. They are brittle, have no luster and they are not good conductors of heat and electricity.

70. a. b. Cd, Cu Br, P c. Group 18

71. 2

In W Fe O a. I am a member of the Boron family with 49 protons. 72. Use a periodic table to help you identify each element. Give its symbol for the answer. a. I am a member of the Boron family with 49 protons. b. I have a total of 74 electrons in an atom. c. I have an atomic mass of 55.847. d. I have 8 neutrons in an atom. In W Fe O

They have the same (BUT NOT IDENTICAL) properties. 73. The elements oxygen, sulfur, selenium and tellurium are all found in the same group (16) on the table. What do we know about the elements in that family? They have the same (BUT NOT IDENTICAL) properties.

74. a. In what family is neon found? b. What do we call those elements in that group? Family 18 Noble gases

3 Which element is a metalloid? 1. S (Sulfur) 3. Si (Silicon) 75. Which element is a metalloid? 1. S (Sulfur) 3. Si (Silicon) 2. Ba (Barium) 4. Br (Bromine) 3

76. Explain what occurs to the atomic number when moving from left to right on the periodic table. Atomic number increases.

Mg A B C P D E F K G H I A B C D E F G H I Fill in the correct number for each letter using the information provided. 77. Element Atomic Number Atomic Mass # of Protons # of Neutrons # of Electrons Mg 12 24 A B C P 15 D E 16 F K G 39 H I 19 A B C D E F G H I

The answers are … Element Atomic # Atomic Mass Protons Neutrons Electrons Mg 12 24 A B C P 15 D E 16 F K G 39 H I 19 12 12 12 31 15 15 19 19 20

1 78. Which three elements have the most similar chemical properties? Ar, Kr, Br K, Rb, Cs B, C, N O, N, Si 1

79. Which element is a noble gas? hydrogen oxygen neon nitrogen 2

80. Explain the difference between an acid and a base. An acid has an excess of H+ ions and a base has an excess of OH- ions. 81. Identify 2 examples of acids. Hydrochloric acid, lemon juice 82. Identify 2 examples of bases. Soap, drain cleaner 83. What does the pH scale measure? The strength of an acid or base.

84. What does it mean when a substance is neutral? It is not an acid or a base. 85. What pH would neutral substance have? 7 86. Which numbers on the pH scale represent an acid? Any number below 7.

87. Classify each of the following as acidic, neutral, or basic pH = 2.3 pH = 6.5 pH = 8.5 pH = 11.7 pH = 13.4 pH = 7.0 acidic acidic basic basic basic neutral

88. Use the solubility curves below to answer the following questions. a. Identify the solutes represented on this graph. HCl and NH4Cl b. Identify the solvent represented on this graph. water c. How many grams of NH4Cl can dissolve in 100 grams of water at 25°C? d. How many grams of HCl can dissolve in 100 grams of water at 10°C? 40 grams 76 grams

Use the solubility curves below to answer the following questions. e. At what temperature can 70 grams of NH4Cl dissolve in 100 grams of water? 85°C f. Explain the relationship between temperature and the solubility of HCl (gas). As temperature increases, the solubility of HCl decreases. g. Explain the relationship between temperature and the solubility of NH4Cl (solid). As temperature increases, the solubility of NH4Cl increases.